1. Field of the Invention
This invention relates to integrated circuit (IC) fabrication technology, and more particularly, to a method of fabricating a capacitor with a low-resistance electrode structure in a mixed-mode IC device.
2. Description of Related Art
Since IC fabrication technology has advanced to the deep-submicron level, a single IC device can now provide a high packing density and functionality. However, the deep-submicron downsizing of the various semiconductor components in the IC device can also affect the performance of the IC device.
A mixed-mode IC device is a type of IC device that includes both analog and digital circuitry on the same device. It typically includes a capacitor element which can function as a switched capacitor filter for the analog circuitry and function as a storage node in the digital circuitry for data storage. The electrodes of the capacitor element are typically formed from doped polysilicon. One drawback to using doped polysilicon to form the capacitor electrodes, however, is that doped polysilicon has a high resistance that still causes the charge/discharge process to be unsatisfactorily slow. The resulting IC device thus has a low performance. Moreover, at the deep submicron level of integration, the electrode resistance is even further increased due to the downsizing of the electrodes, furtherdegrading the IC's performance.